Sidelined from the latter part of last season with an injury to her right shoulder, the third seeded Sharapova had trouble with her serve and made 12 double faults as Knapp broke six times in temperatures in excess of 41 Celsius (106 Fahrenheit).

Nadal crashes through Kokkinakis

Rafael Nadal gave the next generation a lesson in Grand Slam tennis by dismantling teenage talent Thanasi Kokkinakis 6-2, 6-4, 6-2 to cruise into the third round.

A junior finalist at MelbournePark and the US Open last year, 17-year-old Kokkinakis underlined his potential by blazing 21 winners against the world number one to the delight of rowdy home fans at Rod Laver Arena.

Image: Rafael Nadal of Spain plays a forehand in his second round match against Thanasi Kokkinakis of AustraliaPhotographs: Mark Kolbe/Getty Images

Federer canters into third round

Roger Federer spent as little time as he needed and gave Blaz Kavcic a tennis lesson in recording a 6-2, 6-1, 7-6 victory to advance to the third round on Thursday.

Playing under the closed roof of Hisense Arena due to the extreme heat that had earlier suspended play on the uncovered courts, Federer raced through the first set in 26 minutes with a strong service game and by belting 17 winners.

Federer's sixth ranking - courtesy of a sub-par 2013 - had given the impression of a 32-year-old man whose skills may be diminishing as he enters the twilight of his illustrious career.

That presumption was emphatically rejected when Kavcic held two break points in the fourth game of the second set and had Federer scrambling back and forth in a 23-shot rally only for the Swiss to force a forehand error.

Kavcic could not halt the inevitable

The hard-hitting world number 99 simply stood hands on hips slowly shaking his head as if pondering what to do next.

The Slovenian did manage to break on the next point and thrust his arms skyward in mock triumph, though that only served to fire up Federer who won 13 of the next 16 points to clinch the set in 28 minutes.

The third set was a little closer with Kavcic's serve improving markedly but he could not halt the inevitable as Federer ended the 107-minute lesson when he clinched the tie-break 7-4.

Federer will now meet either 31st seeded Spaniard Fernando Verdasco or Russian Teymuraz Gabashvili in the third round.

Image: Roger Federer of Switzerland plays a forehand in his second round match against Blaz Kavcic of SloveniaPhotographs: Matt King/Getty Images

Wozniacki overcomes McHale in surreal encounter

Dane Caroline Wozniacki survived a surreal encounter with American Christina McHale to record a 6-0, 1-6, 6-2 victory on Rod Laver Arena on Thursday and move into the Australian Open third round.

The 23-year-old former world number one had raced through the first set in 28 minutes under the closed roof due to extreme heat only for her game to implode as the 21-year-old McHale attacked her forehand and forced her into errors.

Wozniacki sets up clash with Garbine Muguruza

Just as easily as Wozniacki had won the first set, McHale won the second set in 31 minutes to send it into a decider before the 10th seed took a short break between sets.

The break appeared to settle her down and her high standard of play returned in the final set as she broke McHale twice to clinch victory in 103 minutes and set up a third round clash with Spain's Garbine Muguruza.